In a photolithography process, a pattern formation method using directed self-assembly (DSA) technology (hereinafter, DSA technology) is drawing attention. In this method, a block copolymer is microphase-separated along a guide pattern to form a fine pattern. Thus, pattern formation exceeding the resolution limit of conventional photolithography technology is enabled.
On the other hand, the area of an alignment mark used for alignment in a wafer process is 100 times to 1000 times the area of a device pattern. Thereby, the visibility of the alignment mark in image recognition is improved.
However, in the pattern formation method using directed self-assembly technology, a block copolymer may be applied also to the region of the alignment mark during the process. In such a case, if the block copolymer phase-separates irregularly in this region, the alignment mark will result in having portions of light and dark contrast. In such a state, the function of the alignment mark may be lost.